What type of phenomenon does the Cannizzaro reaction exhibit?

In the following reaction,assign the state for the underlined atom in the products of complete hydrolysis at $R.T.$: $\underline{N}_2O_4 + H_2O \longrightarrow HNO_3 + HNO_2$

Ammonium dichromate on heating gives:

Equivalent weight of $H_3PO_2$ when it disproportionates into $PH_3$ and $H_3PO_3$ is

Assign $A$,$B$,$C$,$D$ from the given type of reaction.
$H_2O_2 \xrightarrow{R.T} H_2O + \frac{1}{2} O_2$

$P_4 + 3NaOH + 3H_2O \to 3NaH_2PO_2 + PH_3$ is an example of